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  • 1
    Online Resource
    Online Resource
    Frontiers Media SA ; 2022
    In:  Frontiers in Plant Science Vol. 12 ( 2022-2-15)
    In: Frontiers in Plant Science, Frontiers Media SA, Vol. 12 ( 2022-2-15)
    Abstract: The accumulation of raffinose family oligosaccharides (RFOs) is a hallmark of plant response to different abiotic stresses, including cold. The synthesis of galactinol, by galactinol synthases (GolS), and raffinose, by raffinose synthases (RafS), are fundamental for stress-induced accumulation of RFOs, but the role of these enzymes in the cold response of grapevine ( Vitis vinifera L.) woody tissues is still unclear. To address this gap in the literature, 1-year-lignified grapevine canes were incubated at 4°C for 7 and 14 days and tissues were analyzed for sugar content and gene expression. Results showed that, in parallel to starch breakdown, there was an increase in soluble sugars, including sucrose, glucose, fructose, raffinose, and stachyose. Remarkably, abscisic acid (ABA) levels increased during cold acclimation, which correlated with the increased expression of the key ABA-synthesis genes VviNCED2 and VviNCED3 . Expression analysis of the VviGolS and VviRafS family allowed the identification of VviRafS5 as a key player in grapevine cold response. The overexpression of VviRafS5 in Saccharomyces cerevisiae allowed the biochemical characterization of the encoded protein as a raffinose synthase with a size of ~87 kDa. In grapevine cultured cells, VviRafS5 was upregulated by cold and ABA but not by heat and salt stresses. Our results suggest that ABA accumulation in woody tissues during cold acclimation upregulates VivRafS5 leading to raffinose synthesis.
    Type of Medium: Online Resource
    ISSN: 1664-462X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2687947-5
    detail.hit.zdb_id: 2613694-6
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  • 2
    In: Frontiers in Plant Science, Frontiers Media SA, Vol. 7 ( 2016-08-08)
    Type of Medium: Online Resource
    ISSN: 1664-462X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2016
    detail.hit.zdb_id: 2687947-5
    detail.hit.zdb_id: 2613694-6
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  • 3
    Online Resource
    Online Resource
    Frontiers Media SA ; 2021
    In:  Frontiers in Plant Science Vol. 12 ( 2021-10-5)
    In: Frontiers in Plant Science, Frontiers Media SA, Vol. 12 ( 2021-10-5)
    Abstract: Secondary metabolic pathways in grape berries are tightly regulated by an array of molecular mechanisms, including microRNA-mediated post-transcriptional regulation. As recently discovered, before being processed into mature microRNAs (miRNAs), the primary transcripts of miRNAs (pri-miRNAs) can encode for small miRNA-encoded peptides (micropeptides – miPEPs) that ultimately lead to an accentuated downregulation of the respective miRNA-targeted genes. Although few studies about miPEPs are available, the discovery of miPEPs reveals a new layer of gene regulation at the post-transcriptional level that opens the possibility to regulate plant metabolism without resorting to gene manipulation. Here, we identified a miPEP encoded in non-mature miR164c putatively targeting grapevine transcription factor VvMYBPA1 (miPEP164c/miPEP-MYBPA1), a positive regulator of key genes in the proanthocyanidin (PA)-biosynthetic pathway, a pathway that competes directly for substrate with the anthocyanin-biosynthetic pathway. Thus, the objective of this work was to test the hypothesis that the exogenous application of miPEP164c (miPEP-MYBPA1) can modulate the secondary metabolism of grape berry cells by inhibiting PA biosynthetic pathway while simultaneously stimulating anthocyanin synthesis. The exogenous application of miPEP164c to suspension-cultured cells from grape berry (cv. Gamay) enhanced the transcription of its corresponding non-mature miR164c , with a maximum effect at 1 μM and after a period of 10 days, thus leading to a more pronounced post-transcriptional silencing of its target VvMYBPA1. This led to a significant inhibition of the PA pathway, mostly via inhibition of leucoanthocyanidin reductase (LAR) and anthocyanidin reductase (ANR) enzymatic activities and VvLAR1 downregulation. In parallel, the anthocyanin-biosynthetic route was stimulated. Anthocyanin content was 31% higher in miPEP164c-treated cells, in agreement with the observed upregulation of VvUFGT1 transcripts and UFGT enzyme activity levels.
    Type of Medium: Online Resource
    ISSN: 1664-462X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2687947-5
    detail.hit.zdb_id: 2613694-6
    Library Location Call Number Volume/Issue/Year Availability
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  • 4
    Online Resource
    Online Resource
    Frontiers Media SA ; 2022
    In:  Frontiers in Plant Science Vol. 13 ( 2022-7-29)
    In: Frontiers in Plant Science, Frontiers Media SA, Vol. 13 ( 2022-7-29)
    Abstract: VviNAC17 is a grapevine transcription factor activated by ABA. Because ABA has been proposed as the main signal modulating the secondary metabolism in grape berry skins, here we postulated VviNAC17 as a positive regulator of secondary metabolism in grape cells. To validate the hypothesis, VviNAC17 was constitutively and stably overexpressed in grape berry suspension-cultured cells of Gamay Fréaux cv. by Agrobacterium -mediated transformation. Targeted transcriptional analyses by qPCR showed that several genes involved the phenylpropanoid ( VviPAL1 ), stilbenoid ( VviSTS1 ) and flavonoid pathways ( VviDFR , VviLAR1 , VviANR , VviLDOX , and VviUFGT1 ), as well as anthocyanin vacuolar transport and accumulation ( VviGST4 and VvMATE1 ) were significantly upregulated in VviNAC17-overexpressing transgenic cells, which translated in the stimulation of a number of enzymatic activities in those pathways. This was the case of phenylalanine ammonia lyase (PAL) and UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT) that were about 2-fold and 3.5-fold higher in VviNAC17-overexpressing cells than in control cells. VviNAC17-overexpressing cells accumulated significantly higher amounts of anthocyanins, proanthocyanidins, total flavonoids and total phenolics. These findings confirmed that VviNAC17 is an important positive regulator of secondary metabolism in grapevine contributing to the accumulation of important berry quality-related secondary metabolites.
    Type of Medium: Online Resource
    ISSN: 1664-462X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2687947-5
    detail.hit.zdb_id: 2613694-6
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  • 5
    Online Resource
    Online Resource
    Frontiers Media SA ; 2021
    In:  Frontiers in Plant Science Vol. 12 ( 2021-8-27)
    In: Frontiers in Plant Science, Frontiers Media SA, Vol. 12 ( 2021-8-27)
    Abstract: Vineyard calcium (Ca) sprays have been increasingly used by grape growers to improve fruit firmness and thus maintain quality, particularly in periods of heavy rains and hail. The observation that Ca visibly modified berry size, texture, and color in the most prominent white cultivar of the DOC region ‘Vinhos Verdes’, cultivar (cv.) Loureiro, led us to hypothesize that Ca induced metabolic rearrangements that resulted in a substantial delay in fruit maturation. Targeted metabolomics by ultra-performance liquid chromatography coupled to mass spectrometry and directed transcriptomics were thus combined to characterize the metabolic and transcriptional profiles of cv. Loureiro berries that, together with firmness, °Brix, and fruit weight measurements, allowed to obtain an integrated picture of the biochemical and structural effects of Ca in this cultivar. Results showed that exogenous Ca decreased amino acid levels in ripe berries while upregulating PAL1 expression, and stimulated the accumulation of caftaric, coutaric, and fertaric acids. An increase in the levels of specific stilbenoids, namely E -piceid and E -ω-viniferin, was observed, which correlated with the upregulation of STS expression. Trace amounts of anthocyanins were detected in berries of this white cultivar, but Ca treatment further inhibited their accumulation. The increased berry flavonol content upon Ca treatment confirmed that Ca delays the maturation process, which was further supported by an increase in fruit firmness and decrease in weight and °Brix at harvest. This newly reported effect may be specific to white cultivars, a topic that deserves further investigation.
    Type of Medium: Online Resource
    ISSN: 1664-462X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2687947-5
    detail.hit.zdb_id: 2613694-6
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  • 6
    Online Resource
    Online Resource
    Frontiers Media SA ; 2022
    In:  Frontiers in Plant Science Vol. 13 ( 2022-10-25)
    In: Frontiers in Plant Science, Frontiers Media SA, Vol. 13 ( 2022-10-25)
    Abstract: The role of photosynthesis in fruits still challenges scientists. This is especially true in the case of mature grape berries of red varieties lined by an anthocyanin-enriched exocarp (skin) almost impermeable to gases. Although chlorophylls are degraded and replaced by carotenoids in several fruits, available evidence suggests that they may persist in red grapes at maturity. In the present study, chloroplasts were isolated from the skin of red grape berries (cv. Vinhão) to measure chlorophyll levels and the organelle proteome. The results showed that chloroplasts (and chlorophylls) are maintained in ripe berries masked by anthocyanin accumulation and that the proteome of chloroplasts from green and mature berries is distinct. Several proteins of the light reactions significantly accumulated in chloroplasts at the mature stage including those of light-harvesting complexes of photosystems I (PSI) and II (PSII), redox chain, and ATP synthase, while chloroplasts at the green stage accumulated more proteins involved in the Calvin cycle and the biosynthesis of amino acids, including precursors of secondary metabolism. Taken together, results suggest that although chloroplasts are more involved in biosynthetic reactions in green berries, at the mature stage, they may provide ATP for cell maintenance and metabolism or even O2 to feed the respiratory demand of inner tissues.
    Type of Medium: Online Resource
    ISSN: 1664-462X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2687947-5
    detail.hit.zdb_id: 2613694-6
    Library Location Call Number Volume/Issue/Year Availability
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  • 7
    Online Resource
    Online Resource
    Frontiers Media SA ; 2020
    In:  Frontiers in Plant Science Vol. 11 ( 2020-6-17)
    In: Frontiers in Plant Science, Frontiers Media SA, Vol. 11 ( 2020-6-17)
    Type of Medium: Online Resource
    ISSN: 1664-462X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2020
    detail.hit.zdb_id: 2687947-5
    detail.hit.zdb_id: 2613694-6
    Library Location Call Number Volume/Issue/Year Availability
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  • 8
    Online Resource
    Online Resource
    Frontiers Media SA ; 2020
    In:  Frontiers in Plant Science Vol. 10 ( 2020-1-27)
    In: Frontiers in Plant Science, Frontiers Media SA, Vol. 10 ( 2020-1-27)
    Type of Medium: Online Resource
    ISSN: 1664-462X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2020
    detail.hit.zdb_id: 2687947-5
    detail.hit.zdb_id: 2613694-6
    Library Location Call Number Volume/Issue/Year Availability
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